Grapes, including raisins, are the third largest crop in California grossing almost $6 billion in 2014. Harvesting the labor-intensive crop takes thousands of workers. But a new raisin grape variety bred in Central California could severely decrease that need for workers.

It takes a lot of hand labor to harvest raisins, three or more rounds of pruning, quality control and picking. And to pay those workers costs a lot of money. That's why the raisin industry is desperately searching for a way to spend less on labor creating a larger profit margin.

Retired USDA plant breeder David Ramming says he thinks he found the answer in a testing field of crossbred raisin grapes near Parlier.

"I happened to notice two plants that the fruit was completely dry and the raisins were approximately the size that we wanted. And we said, 'Wow, eureka!" Ramming says. "One of those has turned out to be Sunpreme."

Ramming discovered Sunpreme in the mid-1990s, after crossbreeding raisin varieties that dry on the vine. The variety eliminates the need for workers to cut and hang grapes and the need for paper trays for sun-drying. Ramming says this could be an answer to labor issues farmers face as the number of workers has decreased.

Sunpreme and other raisin grape varieties are raised in greenhouses in a laboratory at the USDA's Agricultural Sciences Center in Parlier, Calif. (Ezra David Romero/Valley Public Radio)

"It has the potential to make a big impact on the industry, because [of] its ability to naturally dry on the vine without cutting the canes. What that allows is not needing the pruners," Ramming says.

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Ramming says Sunpreme could reduce the need for labor so much that a vineyard that usually takes hundreds of workers could be maintained by just a few people. If the raisin proves cost effective, it could prevent the steady loss of raisin acreage to more profitable crops like almonds or pistachios. Craig Ledbetter is the USDA geneticist who is continuing Ramming's research and release of Sunpreme to growers.

"Basically, the raisin industry desires to be more like the almond industry --being completely mechanized," Ledbetter says. "Using Sunpreme, it is one step closer."

He showed me some of these dry-on-the-vine raisins at the USDA's Agricultural Sciences Center in Parlier, where Sunpreme was born.

"You can see that it's firmly attached to the vine, you can see that it's fully dry at this point in time," says Ledbetter.

But with any new product there are concerns — issues like flavor and color. The Sunpreme raisin is a little lighter in pigment and doesn't have as strong a flavor as the traditional raisin. "It's a meaty grape with a good skin on it," Ledbetter says. "It has a little bit of fruity flavor, it's not a muscat-type raisin, but it has a very pleasant, floral-type flavor."

All grapes, including raisins, are labor-intensive to harvest. Now the raisin industry is looking to the Sunpreme to help dramatically reduce the need for workers. (Ezra David Romero/Valley Public Radio)

Ron Kazarian farms raisins in Fowler, Calif., an agricultural community in the San Joaquin Valley. He says he likes the taste of the Sunpreme and is excited about its release, but he's afraid the raisins will fall off the vine too early.

"This variety is falling down on the ground before the machine even gets in the row," says Kazarain. "What do you think is going to happen when the vine begins to shake? We would be concerned that all the fruit would be on the ground."

He plans to solve that problem by creating a mechanical harvester that picks the crop by shaking the vine and vacuuming raisins off the ground.

Lupe Sandoval, with the California Farm Labor Contractor Association, says the move to mechanization won't be a huge loss to farm laborers.

"With the labor shortage, this will just require some kind of adjustment," Sandoval explains. "There are going to be some workers that will find, 'I'm not going to be a raisin grape worker. I'm going to be a citrus worker.' "

Kazarian, the grower from Fowler, thinks turning to mechanization to harvest his crops increases the probability his farm will be able turn a profit in the future.

"The minimum wage is going up, and it's getting harder and harder every year to deal with the cost of hand harvesting," Kazarian says.

He diversified this year by planting almonds to decrease his reliance on labor. He hopes to plant Sunpreme in 2017, when nurseries are expected to release cuttings of the plant.

Ezra David Romero covers food and agriculture for Valley Public Radio in California. This story first appeared on the station's website.

Copyright 2015 NPR.

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Sunpreme: The Grape That Could Revolutionize The Raisin Industry